Eddy Current Testing Surface Crack On Hub Based On DSP

It is important to accurately measuring surface cracks on wheel hub when the safety and reliability is concerned. Recently, there are many non-destructive techniques that included UT, MT. RT and PT on testing hub surface crack . However these testing techniques have limits, EDDY CURRENT TESTING 's speed is very quick and is suitable to test surface cracks . There is no need to clean surface . So ET is selected for testing ..ET can test surface cracks by testing the change of impedance when the testing coil is near the tested object. Many frequencies many parameters measure is implemented by adding many frequencies sine wave .Wavelet transform is adopted in this thesis. Wavelet transform is very suitable to analysis singularity of the signal because the time domain and the frequency domain of the signal is linked to analysis. In this thesis wavelet transform is used to get rid of yawp and other disturbance and the wavelet transform is modified.Software and hardware design of system of eddy current testing hub surface cracks in this thesis.Neural network is adopted in this thesis. Measure error of width and depth of cracks is little and measure error of distance is more when the data is analysised. But distance measure is used to restrain the disturbance and not affect measure precision.The system is effective on testing simulative hub surface cracks. But more testing data is needed to acquire and analysis.There is more work to do on graphic display.